This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
嶕 combines 山 (mountain) with 焦 (scorch, char), but the exact historical development and original meaning are uncertain.
A mountain 山 that looks scorched 焦, perhaps a rocky peak, but its exact meaning is unclear.
For ショウ, imagine a scorched mountain peak where the heat makes a 'show' of shimmering air: show -> ショウ.
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